宁夏沿黄人工绿洲农田格局对景观多样性的影响——以卫宁平原灌区为例

Analysis of the influence of farmland pattern on landscape diversity in artificial oasis along the Yellow River in Ningxia:a case study in Zhongwei-Zhongning Plain Irrigation District

景观多样性是度量区域生态系统(土地利用/覆盖)类型数量和面积比例的集成指数,是景观生态学研究中使用频率最高的指数。农田作为干旱半干旱区人工绿洲的主要景观组成类型,是近半个世纪绿洲空间结构研究的焦点。本文采用2020年30 m分辨率的土地利用/覆盖数据,借助地理探测器模型的空间分异因子解释力(q统计量)和Moving Window法分析了宁夏沿黄人工绿洲卫宁平原灌区农田格局对景观多样性的影响。结果表明:宁夏沿黄平原区景观多样性(LDI)变化受到了农田总面积(CA)和最大农田斑块指数(LPI)的显著影响,但是它们与斑块间距离(Enn_mn)和斑块类型周长-面积分维数(Pafrac)的交互作用更显著,大于其单独影响。农田总面积和最大农田斑块指数不同级别对LDI都有显著影响;斑块间距离和斑块类型周长-面积分维数分别为67~801 m(q>0.05)和0.142~1.060时对景观多样性影响差异不显著,不在此阈值范围内则对景观多样性有显著影响。

Landscape diversity is an integrated index to measure the type and area proportion of land use/cover in regional ecosystems and the most frequently used index in the research of landscape ecology.As the main landscape component of artificial oases in arid and semi-arid,farmland has been one of the focus of research on the spatial structure of oasis in the past half a century.Based on the land use/cover data with a spatial resolution of 30 m in 2020,this study used the spatial differentiation factor explanatory power(q-statistic)of the geodetector model and method of the moving window to analyze the influence of farmland pattern on landscape diversity in Weining plain irrigation district of artificial oasis along the Yellow River in Ningxia.The results showed that the change of landscape diversity(LDI)in plains along the Yellow River in Ningxia was significantly affected by farmland total area(CA)and largest patch index(LPI),and their interaction with patch euclidean nearest neighbor distance(Enn_mn)and perimeter-area fractal dimension(Pafrac)was more significant than that alone.The grading study of different farmland pattern index showed that CA and LPI at different grade had a significant effects on LDI,Enn_mn and Pafrac between 67-801 m(q>0.05)and 0.142-1.060,respectively,which do not differ significantly in their effect on LDI,while those not within this threshold had a significant effect on LDI.